Tugboat moved by means of two-limbed oars



. paddle 10, connected by the hinge 11, the

Patented Sept. 27, 1927.

UNITED STATES ADOLF EHRLICH, or BUnArns'r, HUNGARY.

TUGBOAI MOVED BY MEANS or TWO-LI1VIBED cans.

Application filed June 11,

My invention relates to tugbo'ats moving by means of oars which are capable to drag onwards a greater load than boats of equal size moved by means of paddlewheels, and which can advance even when grounded and set afloat and drag onwards other grounded boats.

The separate characteristic features of this tugboat will appear from the following detailed description of an example of construction with reference to the accompanying drawings.

Fig. 1 is a side elevation of the tugboat.

Fig. 2 is a plan view of the boat.

Fig. 8 is a front view of a single twolimbed oar.

Figs. 4 and show the different grooves formed on the opposite faces of a cam disc.

Fig. 6 is a section of a cam disc on line L-II of Fig. 5, and of the rods engaging with the respective grooves.

On the deck of the boat 1 an internal CO1D bustion engine 3 is placed. The transversely directed mainshaft 4 of said engine extends on both sides beyond the deck, turning in bearings 33 on lateral frames 2. Parallel to the mainshaft 4, in front thereof and in the same level, an auxiliary rotative shaft 29 is arranged. On the end of the mainshaft a and on the external end of an auxiliary shaft 29 cranks 27 of equal length are carried, both cranks being connected by a link rod 28.

Upon each part of the mainshaft at extending beyond the deck as well as upon each auxiliary shaft 29 equal cam discs 5 are keyed. Each of said cam discs is provided on its both faces with grooves, the groove 6 formed on the external face of each disc differing from the groove 7 formed on the internal face thereof. Behind each cam disc 5 and above the level thereof a transverse stationary shaft 87 is supported by piers 8 resting on the lateral frame 2. On'said shaft 37 an oar is suspended, consisting of the frame shaped handle 9, and the plain entire oar being designed toswing about said transverse shaft 37 alternately forwards and backwards.

The groove 6 formed on the'external face of the rotating cam disc 5 serves to move the entire oarwith reference to the respective stationary shaft 37. To this end the rear end of a driving rod 13 is linked to the frame shaped handle 9 ofthe oar, and a pin 14L projecting from saidtdr'iving rod 1?),- sur- 1926. Serial no. 115,277.

rounded by a roller 15 engages with said groove 6, the enlarged and slotted front end 12 of said driving rod embracing bymeans of a roller 17 the respective rotary shafts a and 29.

The groove 6 formed on the external face of the cam disc 5 consists of two dissimilar sections, one section having twice the angw lar width of an arc than the'other, and the limiting surfaces of both sections forming circular volutes. By reason of this construction of the groove 6, the handle 9 connected with the cam disc 5 by the driving rod 13 is moved during the uniform rotation of the mainshaft t forwards as well as backwards at a constant speed, and the rotation having the direction of the arrows, the speed at which the oar swings backwards is twice the speed of the forward swinging. Owing to the difference in speed the backward swinging oar meets with at least four times the water. resistance in comparison with the forward swinging oar, and consequently the backward swinging oar moves the boat to a far greater extent forwards than the forward swinging oar tends to move it backwards. I

The forward swinging motion of the oar relative to its backward swinging motion is also considerably facilitated by reason of the fact that the curved internal groove 7 of the disc 5 during the forward swinging motion of the oar sets the paddle 10 at right angle with reference to the'handle 9, and brings both again in a line during the backward swinging of the-oar. To this end a connecting rod 18 by means of a pivot 19 surrounded by a roller 20, engages with the conformly curved internal groove 7 of the cam disc 5. The front end of said connecting rod 18 is also enlarged and' provided with a slot 21, and embraces the rotative shafts 4 and 29 respectively by means of a roller 22. The rear end ofsaid rod 18 is hingedly connected to the upper arm of a bell crank lever 23 rocking about the axis 24 on the handle 9. To the lower arm of said bell crank lever 23 is connected the upper end of a link rod 25, the lower end of said link rod being hingedly connected with a projection 26 of the paddle 10'. Owing to this arrangement the oar swings, the shaft 4 rotating in the direction of the arrows, in thebent state with reduced speed forwards, and in the stretched state with twice the speed than forwards alternately backwards;

The swinging oars thus imitating the move ments of striding natural legs, said arrangement enables the tugboat according to the invention to advance when it gets grounded, and set afloat and drag onwards other grounded boats.

The cam disc'keyed on the mainshaft 4; of the power engine and the equal disc on the auxiliary shaft 29 being relatively displaced by 180, one car on the same side of the boat swings forwards while the other performs its backward swinging motion, thus securing the uniform continuity of the advancement. If on each side of the boat three cars be pro vided, each oar being moved by a separate cam disc, the equal grooves on the three cam disc are relatively displaced by 120, whereby an uninterrupted uniform propulsion of the boat is secured.

The tugboat according to the invention may also travel reversely when the cam discs rotate in the reverse direction. The cars then alternately swing, the paddle being set at right angles with reference to the handle, with reduced speed backwards, and the paddle being set in a line with the handle, the oars swing with twice the speed forwards than backwards, moving thus the boat rearwards.

The stretched oar swinging with reference to the body of the boat backwards, acts as a one armed lever, the fulcrum being at its lower end where it encounters the resistance of the water, the motive force acting at the height where the driving rod 13 is linked to the handle 9, and the resistance of thevload to be surmounted appearing atthe top end 37 of the lever. For overcoming the resistance of the water encountered by the backward swinging paddle 10 more motive force is required, consequently the relative traction capacity of the tugboat with ears is the greater, the nearer to the upper end of the entire oar the motive force acts, that is the higher the driving rod 13 is linked to the handle 9. For overcoming a given resistance of the load to be'dragged, appearing at the upper end of said lever, less motive force is required, the nearer to this top end the motive force enacts, therefore for dragging a given load the tugboat with oars according to the invention requires the less motive force the greater its relative traction capacity-is, Thus the tugboat according to the invention differs from the tugboats moved by paddlewheels not only in that the former possesses relatively a greater traction capacity and that it can also advance when grounded, but also therein that the tugboat according to the invention needs less motive force and consequently less fuel for dragging a given load than the tugboat of equal size driven by means of paddlewheels. Two or three two limbed oars arranged on each side of the boat, swinging alternately, supply a paddlewheel with the diameter of twice the length of a stretched two limbed oar, as is shown by the arc of circle drawn interruptedly on Fig. 1 of the accompanying drawing.

I am aware that other modifications besides those shown in the drawing may be found useful and lie Within the scope of my invention.

hat I claim as my invention and desire to secure by Letters Patent is:

1. In a tugboat moved by means of two limbed oars the combination of a. power engine, the transversely directed main shaft of said engine extending on both sidesbeyond the deck and rotating in bearings on a lateral frame, a cam disc keyed on each extending part of said mainshaft, a curved groove on each side face of said disc, an elevated transverse stationary shaft supported by piers resting on said side frame behind each cam disc, a hinged oar, consisting of a frame shaped handle and a plain paddle linked thereto, suspended on each elevated stationary shaft, a horizontally moving driving rod linked to said handle of the suspended oar, a pin projecting from said driving rod opposite the external face of the cam disc and engaging with the groove on said face of the disc, the side walls of said external groove forming involut-es ofa circle, the part of the driving rod extending beyond the projecting pin enlarged and provided with a slot, thereby embracing the main shaft of the power engine a bell crank lever rocking on the. handle of the oar opposite the respective cam disc, the rear end of a connecting rod linked to the upper arm of said bell crank lever, a pin projecting from said connecting rod and engaging with the groove formed on the internal face of the cam disc, the part of said connecting rod extending beyond the projecting pin enlarged and provided with a slot embracing the main shaft of the power engine, a link rod hingedly connecting the lower arm of said bell crank lever with a projection 'of the paddle; the groove on the internal face of the rotating disc thus formed that the link rod engaging therewith sets the paddle of the oar at rightangles to the handle during the forward swinging of the entire ear, and sets the paddle again in a line with the handle during the backward swinging of the oar.

2. In a tugboat of the kind described the combination of a power engine, the transversely directed main shaft of said power engine extending on both sides of the boat beyond the deck and rotating in bearings applied on side frames, auxiliary rotative shafts in front of the main shaft rotating in bearings of said side frame, equal cam discs keyed on the extending parts of the main shaft and on each auxiliary shaft, an elevated stationary transverse shaft'supported by piers behind each rotative cam disc, a two limbed oar suspended on each transverse stationary shaft, a driving rod connecting the groove on the external face of each rotative disc with the handle of the respective car, a bell crank lever rocking on the handle of each suspended oar opposite the respective cam disc, a connecting rod linked to the upper arm of said bell crank lever, and engaging the groove formed on the internal face of the respective rotative disc, the lower arm of said bell crank lever connected by means of a link rod with a projection of the paddle, equal cranks keyed on one end of the main shaft of the power engine and on the external end of an auxiliary rotative shaft, a connecting rod linked to the distal ends of both equal cranks, the cam discs fastened on the main shaft of the power engine and on the parallel auxiliary shaft displaced with respect to the grooves by 180 with reference to each another, whereby the front oar-on each side of the boat swings alternately with the rear ear of the same side forwards as well as backwards,

8. In a tugboat of the kind described the combination of a power engine, the main. shaft of the power engine extending transversely on both sides beyond the deck of the boat, an auxiliary rotative shaft parallel to the main shaft on both sides of the body, equal cranks on one end of the main shaft and on the external end of the auxiliary shaft in front thereof, a rod connecting the revolving ends of said equal cranks, an elevated stationary transverse shaftv behind each rotative shaft, a two limbed oar sus-' pended on each stationary transverse shaft, cam disc keyed on each rotative shaft, a bell crank lever rocking on the handle of each oar opposite the respective cam disc, a

connecting rod linked to the upper arm of said bell crank lever and engaging with the groove formed on the internal face of said cam disc, the lower arm of the bell crank lever connected by means of a link rod to a projection on the paddle of the oar, a hori- Zontally moving driving rod engaging by means of a projecting pin with the groove formed on the external face of the disc, said external groove consisting of two unequal sections, one section having twice the angular width than the other, whereby the oar is adapted to move twice as fast backwards as forwards.

41-. In a tugboat of the kind described the combination of a power engine, the main shaft of said power engine extending on both sides beyond the deck, auxiliary shafts on each side parallel to the main shaft, equal cam discs keyed on the main shaft and on each parallel auxiliary shaft, grooves on both side faces of said cam discs, an elevated stationary shaft behind each cam disc, a two limbed oar suspended on each transverse stationary shaft, the groove formed on the internal face of each disc serving to extend and fold alternately the swinging oars, the groove formed on the external face of each disc serving to swing said two limbed oar alternately forwards and backwards, said oars extending in the extended perpendicular position beyond the bottom of the boat, and the external groove of the cam disc so arranged and the driving rod engaging with said external grooveso dimensioned that the handle of the oar from its temporary vertical position swings at about twice the angular distance forwards as backwards, the extension of the previously folded oar taking place in the foremost swinging position of the oar, whereby the boat is adapted to ad vance when grounded.

In testimony whereof I have signed my name to this specification this 27th day of May, 1926.

ADOLF EHRLICH. 

